Age resister for rubber compounds



Patented Oct. 25, 1932 UNITED STATES PATENT-OFFICE,

ALBERT M. CLIFFORD, F AKRON, OHIO, ASSIGNOR' TO THE GOODYEAR TIRE 8nRUBBER COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO AGE RESISTER FORRUBBER COMPOUNDS No Drawing.

10 ilar deteriorating agencies.

Heretofore, it has been observed that rubber, transformer oils, soapsand similar organic materials are attached by, and gradually deteriorateunder the influence of, at-

sunlight, heat, etc. It has been proposed to overcome these deleteriousefliects by incorporating into the com pounds certain preservativesknown as antioxidants or age retarders. Although many materials havebeen employed for this purpose, the phenyl naphthylamines and similarsecondary amines have been found by actual test to be among the mostsatisfactory for general use.

This invention consists in the discovery that aliphatic substitutedphenyl naphthylamines such as cumidyl and xylyl naphthylamines, eitherof the alpha or beta form, are also excellent anti-oxidants which arepractioally equal in power as preservatives to the unsubstituted amineswhich have heretofore been employed. Substituted amines maybemanufactured by methods analogous to those employed in the manufactureof phenyl naphthylmamines merely by subjecting the naphthol (eitheralpha or beta) to a temperature of 280 to 310 C. in an autoclave for aperiod of eight to ten hours. The reaction products may be purified bywashing them with dilute alkali in order to remove any unreactednaphthol and then following this treatment with P subsequent washingswith water, dilute acid, and finally with water. The product may bedried by subjecting it to distillation under vacuum. 1-3-4-xylyl betanaphthylamine Application filed April 8, 1930. Serial No. 442,713.

obtained in this manner is an orangecolored oily material having aboiling point of 238 to 240 C at a pressure of seven millimeters ofmercury. Gumidyl beta naphthyla-mine is also an orange colored materialhaving a thick sirupy consistency and having a boiling point of 215 to230 C. under a pressure of four millimeters of mercury.- The compoundsare both soluble in benzene, alcohol, acetic acid, etc, and are slightlysoluble-in petroleum ether. All of the solutions are characterized bydeep blue fluorescence.

Although these materials may successfully be employedas antioxidants inmost of the standard rubber compounds, the following is an example of aformula which has been foundby actual test to be quite satisfactory:

Samples of compounds prepared in accordance with .the preceding formulain which cumidyl beta naphthylamine and xylyl beta naphthylamine wereemployed as antioxidants were subjected to vulcanization for varyingperiods of time. One portion of these samples was then subjectedimmediate- 1y to physical tests in order to ascertain the tensilestrength and elasticity thereof prior to aging. I

A second set of exactly corresponding samples were then subjected toartificial aging in an oxygen bomb under pressure of 150 ounds persquare inch and at a temperature of 50 C. for a period of six days.These samples were then removed from the bomb and subjected to physicaltests identical with those conducted upon unaged samples.

The results of these parting from the spirit of tests are tabulated asfollows Load in kgs/cm at l Tensile i i Cure Per cent 7 weight strengthelong. 5007 7007 increase .kgS/cm I elong elong C'umidyl betanaphthylamine ORIGINAL a ss- 9a "890' 14 146 860 20 so r 185 820 26 92 VAGED iN oxmm BOMB 6 DAYS .a'r 50 0. i

as 104 835 15 49 .04 so 147 810 r 23 e so ".1 70 167 760 32 118 .07

I Xylyl beta naphthylamine 'joRIGINaII.

V 35 112' i 905 15 asso I 140 s50 20 5s AGED IN OXYGEN Home 6 DAYS AT 50o.-

,as. V 117 s35 17 5e .06 50 137 785 24 87 02 70 158" 745 I as 122 :14

' It will be'observed that the samples of main which is a cumidyl group.

- April, 1930. 8

composable organic materials which comcanize in the presence of acumidyl naph-' thylamine.

4. As anew chemical compound, a material having the formula J ,III,

In witnesswhereofll have hereunto signed my name at Akron, in the countyof Summit and State of Ohio,

U; S. A., this 7th dayof" IVAL'BERTMT'OLIFFORD. I V

terial containing the new antioxidants are not materially affected bythe action 'of oxygen even'under the relatively severe conditionsexisting in the oxygen bomb. In fact,j it would appear that thecondition of the sample s is somewhatimproved, at least in certaincases, by such treatment. Under simf ilarconditions samples of materialcontainmg no antioxidants are reduced to resinous masses-substantiallydevoid of elasticity and tensile strength.- a The new antioxidants maybe I manufactured at relatively slight expense and trou- I -They alsopossess but rslight, ifany,

ble. odor and are not appreciablytoxic. They blend readily withrubberand alsowith other and soups; in fact the solubility thereofinthylamine, compounds from which they may be considered as being derived.For these mercial'materials. V

Although I have described the preferred reasons, they are highlydesirable as comembodiments of the invention, it will be ap parent tothose, Skilled in the art that it is notflimited thereto but thatvarious modica fieations may be made therein without defrom the scope ofthe appended claims. WhatIclaim isz.

A methodof preserving rubber; transformer oils, soaps," and similarreadily dethe invention or

